Casing scratcher



1959 I F. M. GIST 2,868,298

CASING SCRATCHER INVENTOR. Fred Morgan 61's) ATTORNEYS Jan. 13, 1959, F. M..GIST 2,863,293

CASING SCRATCHER Filed March 18, 1954 2 Sheets-Sheet 2 IN VEN TOR. Fred Morgan Gisf A TTORNEYS United States Patent O CASING SCRATCHER Fred Morgan Gist, Midland, Tex. I Application March 18, 1954, Serial No. 417,190 7 Claims. or. 166-173) result, voids occur in the cement and appreciable portions of the casing are not cemented. Some conditions require and some operators preferrotation of the casing and the scratchers mounted thereon, others reciprocation,

while still others both rotation and reciprocation. Although a variety of casing scratchers have been devised and used heretofore, the same are not universal and different types are required or preferred for various conditions.

Therefore, one object of the invention is to provide an improved casing scratcher of such construction as to be capable of being rotated and/ or reciprocated to efficaciously clean the wall of a well borer n An important object of the invention is to provide an improved 'casing scratcher having spines and flexible means for mounting the spines on a casing in a variety of patterns 'or directions to assure thorough cleaning of a well bore wall. n t

, A particular object of the invention is to provide an improved casing scratcher having a flexible element carrying spines and adapted to be attached to or wound around a casing whereby the spines may extend longitudinally or helically of the casing and may be closely or widely spaced.

Another object of the invention is to provide an improved casing scratcher, of the character described, where in the flexible element may have one or both of its ends or its medial portion fixed against rotation relative to the casing with its other end or both ends relatively free whereby said element and its spines may be disposed in a helix or-reverse helix by rotation of saidcasing in the well bore. n n

'A further object of the invention is to provide an improved casing scratcher, of the character described, wherein the spines are utilized to resist rotation of the scratcher or portions thereof with the casing and wherein the flexible element and spines function to reinforce the cement. A

A construction designed to carry out the invention will be hereinafter described together with other features of the invention.

-The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein examples of the invention are shown, and wherein:

Fig. 1 is an elevational view of a casing scratcher con- 'structed in accordance with the invention and fixedly mounted on a well casing so as to extend longitudinally thereof, r

Fig. 2 is an elevational view ofwthe scratcher fixedly mounted on and extending helically of the casing,

Fig. 3 is anelevational view of the scratcher having its upper end. free of the casing and showing an intermediate stop ring limiting downward movement of the upper end,

Fig. 4 is an enlarged, detailed View, partly in section, showing one manner of securing the flexible element to one of the collars,

Fig. 5 is a fragmentary, elevational view showing the connected collar and element,

Fig. 6 is a horizontal, cross-sectional view, taken on the line 6--6 of Fig. 5,

Fig. 7 is an elevational view of the scratcher having both of its ends free of the casing and its medial portion fixed to said casing with stop rings between the ends and medial portion,

Fig. 8 is a view, similar to Fig. 7, showing the lower end of the scratcher detachably connected to the casing,

Fig; 9 is an elevational view of the lower portion of the scratcher shown in Fig. 8 detached from the casing,

Fig. 10 is a horizontal, cross-sectional view, taken on the line 1010 of Fig. 7, and

Fig. 11 is an enlarged, perspective view showing one 'manner of connecting the, spines to the flexible element.

In the, drawings,the numeral 10 designates acasin-g scratcher embodying the principles of the invention and mounted on a length of conventional well casing 11. Although mounted on the exterior of the casing and used to scratch the wall of a well bore, these and similar devicesrare known and commonly referred to as casing scratchers. The scratcher includes one or more, prefer:

ably two, and diametrically opposed with respect to .the'

casing, flexible elements 12 in the form of wire rope or cable having their ends attached to annular bands or collars 13 carried by said casing. Although subject to variation, the ends of the flexible elements 12 may be connected to each collar 13 by radial eye or socket members 14 welded or otherwise secured to the exterior of the collar in diametrically-opposed relationship. Preferably, each socket 14 is of inverted, substantially semi-conical shape so as to be tapered from an enlarged outer end to a reduced inner end (Figs. 4 and 5). As shown by the numeral 15, the ends of the flexible element are frayed or unwound and secured in the tapered sockets by babbit or other suitable bonding material 16 (Fig. 6). A plurality of spines 17 are carried by each flexible element at spaced intervals and, preferably, each spine includes a plurality of resilient arms or fingers 18 extending radially or transversely from the element and may be formed of single wires or a plurality of wires 19 of small gauge, twisted or wound in rope form (Fig. 11)., It is noted that each finger is resilient and has considerable length as compared to its diameter. The fingers are flexible enough to bend and wipe or drag on the incrustation or accumulation on the wall of the well bore when the casing is rotated or reciprocated. The spines 17 may be woven in the element or extend therethrough and be wrapped around said element as shown by the numeral 20. Of course, the mounting or manner of attachment is subject to variation as is the spacing between the spines.

The end collars 13 may be fixedly mounted on the casing 11 by welding 21 or other suitable means and the flexible elements 12 may extend longitudinally of said casing in a comm-on plane or diametrically opposed relationship as shown in Fig.1, whereby the scratcher is adapted to clean thewall of a well bore upon rotation of the casing prior to cementing. In order to permit cleaning my reciprocation of the casing, the flexible elements may be wrapped around said casing in helices 22 prior to securing Patented Jan. 13, 1959.

amazes a one or both of the collars (Fig. 2). It is noted that the elements may be of any suitable length and that several scratchers of the same or different arrangement are used on the same casing since the cement is usually many feet inlength. Although the spines 17 may project radially from the flexible elements, it is pointed out that said spines extend tangentially with respect to the casing whereby the same are subjected to less stressso as to minimize the deformation and fracture of said spines.

If desired, the elements 12 may be, wound around the casing 11 in the well bore and, in this event, an end collar 23 may be loosely mounted on the casing in place of the upper collar so as to be slidable and rotatable thereon as shown in Fig. 3. A plurality of spines 24, similar to spines 17 and having their fingers or arms extending substantially tangentially, may be welded or otherwise secured on the exterior of the upper collar 23 to resist rotation and longitudinal movement of said collar and the upper portion of the scratcher. The upper collar has similar radial eyes 25 for connection with the upper ends of the elements. A stop band or ring 26 is welded or otherwise fixedly mounted on the casing between the collars for limiting downward movement of the upper collar. Upon rotation of the casing and the lower collar 13, the frictional engagement of the spines 24 with the walls of the well bore tends to hold the upper collar 23 and the upper portion of the elements stationary whereby said elements are wound around the casing in helices 27. To some extent, the spiraling of the elements is assisted by the frictional engagement of their spines 17 with the Well bore Wall. Of course, the stop ring 26 limits downward movement of the upper collar and the spiraling of the elements.

Another mounting of the flexible elements of the casing scratcher 'is shown in Figs. 7 and 10, which includes the upper, loosely-mounted collar 23 and stop ring 26 of Fig. 3. A loose, lower collar 28, having similar spines 29, and radial ears 30 for connection with the elements, and a similar stop band or ring 31 are substituted for the lower stationary collar 13. Intermediate the stop rings 26 and 31, a collar 32 is fixedly mounted on the casing 11 by welding 33 or other suitable means. Being similar to the collars 13, the collar 32 includes similar radial eyes 34 and 35 for receiving and confining the intermediate portions of the flexible elements 12. In order to facilitate installation, the elements may be formed in upper and lower sections 36 and 37 with their inner ends secured in the eyes. For receiving the inner or lower ends of the upper element sections 36, the ears 34 are reversed relative to and are disposed between the ears 35 in diametrically opposed relationship to each other. of the casing, the element sections 36 are spiraled in one direction and the element sections 37 are wound in the opposite direction due to the loose mounting of the end collars 23 and 28 and the fixed mounting of the intermediate collar 32. As has been explained, the spines 24 and 29 resist rotation and longitudinal movement of the end collars and are assisted by the spines 17. Longitudinal movement of the end collars is limited by the stop rings 26 and 31. Due to the'reverse helices of the element sections 36 and 37, this form of the scratcher may be employed in cleaning the wall of a well bore by rotation and/or by reciprocation of the casing.

Figs. 8 and 9 represent another arrangement or modification of the casing scratcher 18, which includes the upper end collar 23, the upper and lower stop rings 26 and 31, the intermediate collar 32 and the upper and lower section 36 and 37 of the flexible elements. Instead of the lower end collar 28, a collar 38 is provided and has similar spines 39 and radial ears 40 for connection with the ends of the element sections 37. An annular boss or shoulder 41 is welded or otherwise secured on the casing 11 and has a coarse screw-thread 42 for engagement by a complementary screw-thread 43 formed in the bore of the collar 38. With this arrangement, the scratcher may belowered inthe well bore to the approximate point of use prior to spiraling of the flexible elements. The

Upon rotation screw-threaded connection between the collar and the shoulder boss 41 holds said collar and the element sections 37 against upward relative movement upon lowering of the casing and scratchers. When desired, the collar 38 may be detached from the casing by rotation due to the frictional resistance or drag of the spines 39 (Fig. 9) which is assisted or supplemented by the spines 17 of the element sections 37. Again, it is noted that the longitudinal movement of the end collars and spiraling of the flexible elements or their sections are limited by the stop rings.

From the foregoing, it should be readily apparent that a novel casing scratcher has been provided. Due to the use of flexible elements, wire rope or cable, the scratcher may be mounted in a number of different ways. The spines may be arranged longitudinally or helically of the casing or in any combination of such arrangements and the helices may be identical or reversed. Necessarily, as used herein the word longitudinal includes the helically arranged elements as well as the diametrically opposed elements shown in Fig. 1. Also, the flexible elements may be fixedly mounted or loosely or detachably mounted for arrangement upon or after insertion in the well bore. Although a number of modifications are shown and described, it is obvious that many other arrangements and combinations could be devised. It is pointed out that it is customary to employ a plurality of scratchers on the same casing for cleaning a well bore prior to cementing and that the scratchers may be identical or of various arrangements. Of course, the length and tautness of the flexible elements are subject to variation and said elements perform satisfactorily when relatively loose. Due to the use of the flexible elements, the scratcher may be of any desired length and may extend throughout one or more joints of casing. The construction of the scratcher, particularly the longitudinal spacing of the spines, provides minimum obstruction so as to reduce the possibility of accumulating sufiicient drilling fluid and/or loose formation to close or plug the annular space between the casing and well bore, whereby there is no interference with movement of said casing and circulation. By varying the positions of the stop rings, with respect to the end collars, the convolutions of the flexible elements and the spacing of the spines may be altered. For example, the convolutions are greater and the spacings are less in Fig. 7 than'in Figs. l-3 whereby the former is adaptable for use in cleaning by reciprocation as well as by rotation of the casing. Also, the number of spines and their spacing are variable. It is noted that the flexible elements, spines and collars of the scratcher provide a continuous reinforcement for the cement throughout an extended length. The primary feature of the invention resides in the flexible construction of the casing scratcher which permits mounting in a multiplicity of arrangements.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

l. A casing scratcher including end supports mounted on the exterior of a well casing, an elongate flexible element having its ends fixed to the end supports and free from support between its ends, and elongate resilient fingers directed outwardly from thefiexible element in spaced relation to one another, each finger having its major portion spaced from adjacent fingers, whereby unimpeded circulation of fluid alongthe length of the casing is provided.

2. A casing scratcher as set forth in claim 1 wherein the flexible element is formed of wire rope and the fingers include elongate wires secured to the rope.

3. A casing scratcher as set forth in claim 1 wherein the resilient fingers are formed of twisted wires of suflicient length to project appreciably from the flexible element: 1 I i 4. A casing scratcher including a pair of collars mounted free from support between said collars, and elongate resilient fingers connected to the rope in spaced relation to one another and directed outwardly from said rope, each finger having its major portion spaced from adjacent fingers, whereby unimpeded paths across the rope and between the fingers are provided.

5. A casing scratcher as set forth in claim 4 wherein one of the collars is rotatable and movable longitudinally relative to the casing whereby the wire rope may be wound around the casing in a helix.

6. A casing scratcher as set forth in claim 5 wherein groups of resilient fingers are mounted on the relatively movable collar for resistingmovement of said collar with the casing.

7. A casing scratcher including 'a pair of spaced collars mounted on the exterior of a casing, a pair of elongate wire ropes extending longitudinally of the casing on opposite sides thereof and having their ends fixed to the aeea'aoa collars and free of support between the collars, and elongate resilient fingers connected to the rope in spaced relation' to one another and directed outwardly from said rope, each finger having its major portion spaced from adjacent fingers, whereby. unimpeded paths across the ropes and between the fingers are provided.

References Cited in the file of this patent UNITED STATES PATENTS 102,374 Coyle Apr. 26, 1870 1,040,118 Batt Oct. 1, 1912 1,484,027 Jacobs Feb. 19, 1924 1,572,769 Clark Feb. 9, 1926 1,677,050 Reed et al. July 10, 1928 1,704,364 Markley Mar. 5, 1929 2,503,719 Garrison Apr. 11, 1950 2,606,338 Lorenzo Aug. 12, 1952 2,683,491 Gassaway 'July 13, 1954 2,687,178 Atkinson Aug. 24, 1954 FOREIGN PATENTS I 362,614 Great Britain Dec. 10, 1931 

